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August 5, 2011

Scientists Create Artificial Sperm From Stem Cells

by Sam Savage

Fertility scientists have created artificial sperm using stem cells for the first time in a breakthrough that could lead to new treatments for infertile men.

In the revolutionary experiments, the Japanese researchers at Kyoto University have made sperm from scratch, and, for the first time, successfully used it to produce healthy baby mice. The landmark research paves the way for new drugs for infertility -- a condition that affects one in six couples.

When the sperm cells were transplanted into the testicles of infertile mice, the cells produced normal-looking sperm. Researchers, led by Dr Katsuhiko Hayashi and Mitinori Saitou, injected the sperm into mouse eggs and implanted them into female mice, which give birth to healthy pups.

The baby mice, once they grew up, were capable of reproducing naturally, according to the study, published in the journal Cell.

Previous studies to create sperm from embryonic stem cells have not been successful, and, in most cases, led to unhealthy offspring which died soon after birth.

"This is quite a step forward in developing a process by which sperm could be made for infertile men, perhaps by taking as a starting point a cell from their skin or from something like bone marrow," said fertility expert Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield.

"Clearly more work needs to be done to refine this process, but it's hugely exciting," he said.

British laws ban the use of lab-made mature sperm in fertility treatments. But the innovative technique actually creates germ cells which produced sperm naturally.

"The philosophy of the law is to stop that kind of thing happening. But in this case you're not technically creating sperm, so it might be that you can sidestep this regulation. It all depends on definition," Pacey told the Telegraph.

Dr Jane Stewart, British Fertility Society spokesperson and consultant gynecologist at Newcastle Fertility Center said the ability to create human sperm-producing cells in the lab would be a "landmark achievement" in fertility treatments.

"This publication in an animal model marks a further step towards this goal, however as the authors clearly point out much work remains to be done," she said.

The team of researchers suggest the same procedure could be carried out using stem cells derived from adult skin cells.

"Many research groups have attempted to re-create the process of sperm production in the laboratory using stem cells as the starting material," said Pacey. "This has huge implications for furthering our understanding of how sperm are made, but may also one day lead to a clinical application whereby we could make sperm for infertile men."

"Sadly, so far, none of the attempts to make sperm from embryonic stem cells have been hugely successful, although we have learned much about some of the cellular processes involved," he added.

The Kyoto study was "quite a large step forward" in developing a process by which sperm could be made for infertile men, perhaps by taking as a starting point a cell from their skin or from something like bone marrow.

But the technique also opens a Pandora's box of ethical dilemmas. Concerns raised range from men being made "redundant" from the process of creating life, to babies being created through entirely artificial means. And has also gotten the attention of critics who question whether it is a good idea to mess with the building blocks of life just so couples can satisfy their desire to have children.

Despite concerns, the researchers hope to be able to repeat their success using slivers of skin as starting material, allowing men to father children that are genetically their own. They also want to try to create eggs. Unlocking the secrets of sperm and egg production could also lead to "Ëmiracle' pills that boost fertility and help millions of couples.

Defects in sperm and egg development are the biggest cause of infertility but, because many stages occur in the womb, scientists have struggled to study the process in detail.

Dr. Saitou cautioned the work is preliminary and much more research is needed before the process could be applied to humans.

"Our work is still a purely scientific achievement using the mouse and the application of this work to human material involves a lot of more work, time and ethical discussion," he told the Daily Mail.